Question

The standard emf for the cell reaction

$Zn + Cu^{2 +} \rightarrow Cu + Zn^{2 +}$is 1.1 volt at $25^{o}C$.

The emf for the cell reaction, when 0.1 M $Cu^{2 +}$and 0.1 M $Zn^{2 +}$ solution are used, at $25^{o}C$is

• A. 1.10 V
• B. 0.10 V
• C. –1.10V
• D. –0.110 V

Answer 1

Answer: (A)

1.10 V

Answer 2

$E_{cell} = E_{cell}^{0} - \frac{0.0591}{n}\log\frac{\left\lbrack Zn^{2 +} \right\rbrack}{\left\lbrack Cu^{2 +} \right\rbrack}$

$\mathbf{E}_{\mathbf{cell}}\mathbf{= 1.10}\mathbf{-}\frac{\mathbf{0.0591}}{\mathbf{2}}\mathbf{\log}\left\lbrack \frac{\mathbf{0.1}}{\mathbf{0.1}} \right\rbrack$

$\mathbf{E}_{\mathbf{cell}}\mathbf{= 1.10V(}\mathbf{\because}\mathbf{\log}\mathbf{1}\mathbf{= 0)}$